[PATCH v2 2/6] mtd: spi-nor: add erase die (chip) capability

[Fabio Estevam]

On 03/11/2023 10:48, Tudor Ambarus wrote:

> Yep, it's strange, we'll have to check what's happening. I found my
> n25q00 flash, on my side all its 4 dice are erased in 5 sec.  SFDP
> defines how long the erase die should take, see BFPT dword 11. You can
> start with that.

Where does BFPT dword 11 reside inside SFDP?

~# hexdump -C 
/sys/devices/platform/soc at 0/30800000.bus/30bb0000.spi/spi_master/spi0/spi0.0/spi-nor/sfdp
00000000  53 46 44 50 06 01 01 ff  00 06 01 10 30 00 00 ff  
|SFDP........0...|
00000010  84 00 01 02 80 00 00 ff  ff ff ff ff ff ff ff ff  
|................|
00000020  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  
|................|
00000030  e5 20 fb ff ff ff ff 3f  29 eb 27 6b 27 3b 27 bb  |. 
.....?).'k';'.|
00000040  ff ff ff ff ff ff 27 bb  ff ff 29 eb 0c 20 10 d8  
|......'...).. ..|
00000050  0f 52 00 00 24 4a 99 00  8b 8e 03 e1 ac 01 27 38  
|.R..$J........'8|
00000060  7a 75 7a 75 fb bd d5 5c  4a 0f 82 ff 81 bd 3d 36  
|zuzu...\J.....=6|
00000070  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  
|................|
00000080  ff e7 ff ff 21 dc ff ff                           |....!...|
00000088

Do we need a fixup to tell the erase die to be faster?

I haven't found the 'BFPT' term in the JEDEC spec.

> real	0m5.485s
> user	0m0.000s
> sys	0m5.461s

Before erasing, did the flash contain 128MB of random data on your test?

On my tests, when the flash contains 128MB of random data, the first 
erase
takes 4 minutes. Subsequent erases take only 2 seconds.

Thanks